Bilateral facilitation of motor control in chronic hemiplegia

The present study addressed the efficacy of concurrently moving both arms, with and without a load added to the uninvolved arm, in facilitating the quality of movement of the involved side in individuals with moderate, chronic hemiplegia. Six hemiplegic cerebrovascular accident (CVA) subjects with left-hemisphere lesions participated in the study. The four males and two females ranged from 46 to 77 years of age and 30–96 months post-CVA. All subjects scored at least 70% on the Fugl-Meyer test of motor function. The task was to perform discrete unilateral and bilateral elbow extensions in the horizontal plane. The movements were 45° in amplitude and were to terminate in a 10° target zone that was indicated by an illustration of a coffee mug. The instructions were to move toward the mug as smoothly as possible in a movement time (MT) determined to be 20% longer than their minimal MT for that distance. The primary dependent variable was the percentage of continuous vs. discontinuous trajectories observed in each condition, based on whether or not a transient hesitation or reversal was observed. Phase of peak velocity was also quantified as a general indication of the symmetry of the velocity profile. Three of the six subjects exhibited a greater percentage of continuous movements of the involved arm in the nonloaded bilateral condition than the unimanual condition. Five subjects benefited when the uninvolved arm was inertially loaded in the bilateral condition when compared with unimanual performance. Only the oldest subject failed to exhibit facilitation. Peak velocity phase tended to normalize toward symmetry in the bilateral conditions. These findings are consistent with prior evidence that the control of the involved arm improves during bimanual performance for some hemiplegic subjects. It further suggests loading the uninvolved arm may benefit some subjects with respect to unimanual performance, with age perhaps playing a role in determining efficacy.     

Preserved visual lexicosemantics in global aphasia: a right-hemisphere contribution?

Extensive testing of a patient, GP, who encountered large-scale destruction of left-hemisphere (LH) language regions was undertaken in order to address several issues concerning the ability of nonperisylvian areas to extract meaning from printed words. Testing revealed recognition of superordinate boundaries of animals, tools, vegetables, fruit, clothes, and furniture. GP was able to distinguish proper names from other nouns and from nonwords. GP was also able to differentiate words representing living things from those denoting nonliving things. The extent of LH infarct resulting in a global impairment to phonological and syntactic processing suggests LH specificity for these functions but considerable right-hemisphere (RH) participation in visual lexicosemantic processing. The relative preservation of visual lexicosemantic abilities despite severe impairment to all aspects of phonological coding demonstrates the importance of the direct route to the meaning of single printed words.     

Afferent dysgraphia after right cerebral stroke: an autonomous syndrome?

Afferent dysgraphia is an acquired writing deficit characterized by deletions and duplications of letters and strokes. The commonly accepted interpretation states that afferent dysgraphia is associated with three main clinical features: production of spatial writing errors; the presence of left unilateral neglect; and no deterioration in performance when writing blindfolded. In order to test whether these symptoms necessarily co-occur with afferent dysgraphia, we studied the writing performances of a series of eight right brain-damaged patients. In sentence copying, spontaneous handwriting, and writing to dictation they showed afferent dysgraphia. However, signs of left neglect and spatial dysgraphia were evident only in some cases. Furthermore, the frequency of afferent errors increased when patients were required to write without vision. The present study demonstrates that afferent dysgraphia is an autonomous clinical entity and that it results from a selective impairment of a mechanism whose function is that of comparing the information about the number of letters and strokes specified at the level of letter motor programs and the actual number of movements already realized.     

The Electroconvulsive Therapy Controversy: Evidence and Ethics

The author reviews literature pertaining to the efficacy and safety of electroconvulsive therapy (ECT), with emphasis on the controversy concerning whether ECT causes brain damage. ECT does appear to be effective in the treatment of severe depression and possibly mania. The types of memory problems caused by ECT are discussed, and evidence suggests that most of these deficits are transitory. Although most evidence points toward modern ECT not causing brain damage, there are still some findings that raise questions about safety. Ethical issues involving this treatment's use, its availability to the public, and informed consent procedures are discussed.     

Attack and defense in conspecific fighting in tree shrews (Tupaia belangeri)

Principles of conspecific defense have been analyzed for rodents, in which specific target sites for biting by attackers on defenders serve as an important determinant of the actions involved in both attacker and defender behavior. In an effort to determine the generality of these principles, attack and defensive behaviors and target sites for biting attack were evaluated in a nonrodent species, the tree shrew (Tupaia belangeri). Brief daily and repeated conspecific dyadic encounters between adult, socially experienced males (dominants, attackers), and adult, socially naive males (subordinates, defenders) that had been transferred into the territory of the dominants, produced a polarization of attack and defense. The dominant males showed chase, chase attack, jump attack, and biting behaviors, while the subordinates displayed flight and freezing. The vast majority of bites, as well as wounds and bruises, were on the subordinates’ backs. These patterns are very similar to those previously found in rats and mice and suggest that the organization of fighting, with targets of biting (or other painful) attack serving as an important determinant of both attacker (dominant) and defender (subordinate) behavior, may show considerable generality across nonrodent as well as rodent species. Although relatively few wounds were found after 28 days of repeated and daily encounters, the subordinate tree shrews show a variety of behavioral, neuroendocrine, and central nervous changes, indicating that they are stressed by these encounters per se. Aggr. Behav. 27:139–148, 2001. © 2001 Wiley‐Liss, Inc.     

FOK产生机制的再验证

通过用有意义联系和无意义联系的两种中文词对作为识记材料,在以前实验研究基础上,进一步验证关于FOK(Feelingof Knowing)产生机制的两种理论假说,即靶项日记忆强度假说(或靶项目提取可能性假说)与线索熟悉性假说。实验结果表明,靶项目记忆强度和线索熟悉性程度都能决定FOK判断等级的高低,说明两种假说并非绝对对立,非此既彼。但此二因素都需达到一定程度,才能显著影响FOK判断等级的高低。     

开展活体器官移植的伦理学思考

活体器官移植起源于器官移植技术的最初阶段,目前已经成功开展了肾脏,肝脏,肺脏、小肠、脾脏等器官的活体移植手术,事实表明该技术不仅有其科学依据,而且有其伦理学依据,即以人类自身伟大的奉献精神来关爱他人。但开展这一技术时务必需要遵循知情自愿原则,生命价值原则,利益和风险并存原则。当然在积极肯定这一技术的同时,也应该看到这一技术也存在一些伦理学方面尚未解决的问题。     

Who shall be Allowed to Give? Living Organ Donors and the Concept of Autonomy

Free and informed consent is generally acknowledged as the legal andethical basis for living organ donation, but assessments of livingdonors are not always an easy matter. Sometimes it is necessary toinvolve psychosomatics or ethics consultation to evaluate a prospectivedonor to make certain that the requirements for a voluntary andautonomous decision are met. The paper focuses on the conceptualquestions underlying this evaluation process. In order to illustrate howdifferent views of autonomy influence the decision if a donor's offer isethically acceptable, three cases are presented – from Germany, theUnited States, and India. Each case features a person with questionabledecision-making capacity who offered to donate a kidney for a siblingwith severe renal insufficiency. Although the normative framework issimilar in the three countries, different or sometimes even contraryarguments for and against accepting the offer were brought forward. Thesubsequent analysis offers two explanations for the differences inargumentation and outcome in spite of the shared reference to autonomyas the guiding principle: (1) Decisions on the acceptability of a livingdonor cannot simply be deducted from the principle of autonomy but needto integrate contextual information; (2) understandings of the wayautonomy should be contextualized have an important influence on theevaluation of individual cases. Conclusion: Analyzing the conceptualassumptions about autonomy and its relationship to contextual factorscan help in working towards more transparent and better justifieddecisions in the assessment of living organ donors.     

器官移植伦理审查委员会实践难题的伦理思考

器官移植伦理审查委员会在器官移植技术的临床应用中意义重大,但其在实践中面临着缺乏明确的伦理原则和沟通技巧、对需要审查内容的理解不深刻等难题,这影响了其伦理使命的充分实现。为此,伦理审查委员会必须制定明确的伦理原则、深入理解需审查的内容、在伦理学知识、行动纲领和沟通技巧方面对其成员进行培训。     

论移植医学新角色——移植协调员的工作职责

随着移植医学的蓬勃发展,许多国家纷纷制定了人体器官捐赠和移植法令,建立了移植协调机构等配套管理措施和制度。随之,一个新型的专业角色——移植协调员应运而生。在研究国外移植协调员的工作基础上,借鉴国外的经验和模式,根据我国实际状况,提出我国移植协调员的工作职责。